Our long term goals are: (A) to solve the control mechanism of bacterial division using Escherichia coli: precise sequences of events leading to cell division, involving positive and negative regulatory factors and constituents of the septum, (B) to characterize membrane proteins X and Y, which have been shown to be related to cell division and DNA replication. This will be done by purifying both proteins after they are solubilized by nonionic detergents. Biochemical activities and chemical compositions of these proteins, and location of these proteins on cell surface will be investigated. (C) isolation and biochemical studies of other membrane proteins, which enable us to understand functions of membrane and to reconstitute membrane structure. Purification of membrane proteins will be attempted: Differential solubilization of them with use of nonionic detergents, followed by column chromatography or gel electrophoresis. Purified proteins will be investigated from biochemical points of views, such as biochemical activities, chemical compositions, interaction with other proteins, lipid, polysaccharide and peptidoglycan.